I wrecked my hatch a few months ago and just picked up a 4door cheap. It has a D15B non-vtech and still DPFI. I plan on using that bottom end since my Y8 bottom end is busted. My goal is to boost this engine with completely stock internals in the block and head (6-8 psi). in the long run would the Y8 be a better head or my spare A6? I know the Y8 has a smaller combustion chamber which will yeild higher compression. With a small turbo would the A6 have more potential?

I have just converted the car to manual with an 88 SI transmission and the only thing left to do is the MPFI and head swap. Also how does the A6 compare with the factory D15B non-Vtech head?

 

The a6 head is most likely identical to the d15b non vtec head.

 

Depends on if you think going to VTEC is worth the work involved or not . . .

On a turbo motor, when you already have the pm3/non-vtec head, etc it would be harder for me to say it's worth it as any slight power difference lost to the y8 stuff can easily be made up by turning the boost up a pound or two.

Personally, I would go with whatever you already have. Also, as v4lu3s noted the heads are the same on the a6/b2/b1s.

 

I don't think they are completely the same. the A6 head on the d15b2 block made way more power than the stock d15b2 did with its factory head. I know the cams are different and that's what i'm most curious about. I will be using a pm6 ECU along with the MPFI swap, later switching to obd-1 with a p28 when I get a turbo setup. I have all the parts including the d15b head thats already on the engine in the car, the A6 head that came on my old hatch I wrecked, and the Y8 head thats on the broken block I pulled out of my old hatch.

I know changing nothing else the Y8 will make more power leaving the car NA, but adding 6-10psi and a tune on a p28 will the A6 make more power as well as being easier to tune for? or is the Y8 a better head to make power with a turbo?

 

How do you even come to that conclusion?
The DPFI intake is what really kills the power on the D15B2.
That's why the MPFI conversion is so popular.


It is obvious that you haven't studied up on turbo much at all. 6~10 psi is meaningless by itself. A large turbo will put down a lot more power than a small turbo at the same psi.
You need to be setting your goals by power numbers.

The Y8 head has nice quench zones which are a good feature for reducing detonation. Unfortunately, the Y8 head has no-so-good porting on the intake side.

I would go with the B2/A6 head. They are the EXACT same casting.


The P28 is a vtec ECU. What kind of tune are you going to throw on it?
Loading a basemap as your tune is not smart.
You need to get somebody to do a custom tune if you want this to be right.

 

I was refering to a factory d15b2 with a MPFI swap done vs putting the A6 head on the b2 bottem end. it made more power. I know the b1/b2/a6 heads are the same casting, but valvesprings and cams are different, which is why im wondering if an A6 head with its cam is better for a turbo setup than a Y8 head with its vtec cam.

My goal is 200hp on stock internals. I will have the p28 tuned by speedfactory, a shop in my area. At the moment I do not know which turbo I will use but will probably be a td04 from a eclipse or possibly a subaru turbo. I work for a wrecking yard so getting good factory turbos cheap are easy. I want to avoid no-name ebay turbos.

I read that the d16y8 can handle about 200-220 with a good tune on stock internals but I dont know much about the d15b engine other than its basically the same as the d15y7.

 

Sry to jump....new here and to civic world. was given an EF hatch d16y8z I was told but the ID on the block has been shaved smooth but it is a vtec head? how to you tell which head you got anyway? Thx Jon

 

Please dont thread jack, but the d16y8 is a vtec engine. the y7 looks very similar and with a shaved block (very suspicious) the only real way to tell is pull the head stamp and google, or look for the vtec solenoid on the head. google what they look like if you don't know.

y8 will have a P2J stamp. z6 head should have a p08 stamp. and a y7 will have a p2f stamp the y7 is a non-vtech motor but the spark plug holes are facing the front of the moter like a vtec head.

 

Thx Again and sry